JPH01123737A - Agricultural clouding free coated material - Google Patents

Abstract

PURPOSE:To improve resistance weathering resistance, dust protective characteristic and mechanical strength and also to maintain the clouding-free characteristic, by providing an coating layer including fine particles of silica, etc., as well as clouding-preventing agent on an activated surface of a film of ethylene- tetrafluoroethylene group copolymer. CONSTITUTION:A copolymer of ethylene-tetrafluoroethylene group including ethylene/tetrafluoroethylene by 40/60-60/40 molar ratio is extruded at the resin temperatures of 320 deg.C, to be formed into a film having the thickness in the range 10-30mu. One surface of the film thus obtained is treated by corona discharge, which is then coated with a solution which is obtained by adding a polyvinyl alcohol to an aluminasol and diluting the same by 15 times with water to obtained the subject coated material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to agricultural coating materials, and more specifically, a coating layer containing an antifogging agent is provided on a fluororesin film subjected to 1ifii8 civil activation treatment. This is an anti-fog agricultural covering material characterized by:

[Conventional technology]

Traditionally, agricultural covering materials include plastic films such as polyvinyl chloride resin films and polyethylene resin films, glass, or plastic plates reinforced with glass fibers. Among these, plastic films are light and It is generally used because it is cheap and easy to construct, but the following runners-up can be cited.

1. The weather resistance of the film is poor and it cannot be stretched for a long period of time.

The film gets dirty easily and the light transmittance decreases in a short period of time.

3. Water droplets adhere to the film surface, reducing light transmittance.

The anti-fog effect is not sustainable over a long period of time.

[Problem to be solved by the invention]

The purpose of the present invention is to solve the above-mentioned drawbacks of the prior art, and is to provide a material that has excellent weather resistance, dustproofness, and transparency, can be extended for a long period of time, and has an excellent long-term sustainability of the anti-fogging effect. The purpose of this project is to provide agricultural covering materials.

[Means for solving problems]

The present invention has been made to solve the above-mentioned problems, and is characterized in that a coating layer containing an antifogging agent is provided on the treated surface of a fluororesin film whose at least one surface has been surface-activated. The present invention provides an anti-fog agricultural covering material.

The present invention will be explained in detail below.

The fluororesin used in the agricultural coating material of the present invention is a general term for synthetic resins obtained by polymerizing olefins containing fluorine, and in the present invention, the fluorine content is generally 45% by weight or more, particularly 50% by weight. Those mentioned above are preferably used.

Examples of such fluororesins include ethylene-tetrafluoroethylene copolymers, ethylene-chlorotrifluoroethylene copolymers, hexafluoropropylene-tetrafluoroethylene copolymers, and perfluoroalkyl vinyl ether-tetrafluoroethylene copolymers. copolymers, polyvinylidene fluoride, polyvinyl fluoride, etc., and any of these can be used in the present invention, but among them, ethylene-tetrafluoroethylene copolymers are preferred.

The ethylene-tetrafluoroethylene copolymer is a copolymer of ethylene and tetrafluoroethylene as the main components, and a third comonomer component of ethylene/tetrafluoroethylene or less. /The molar ratio of tetrafluoroethylene is 40/
60-60/40. Preferably 45155 to 55/45
Within the range of G, and the formula CH2-CH-C, Fi Peng +
1 (herein, O is an integer from 2 to 10) (for example, CH
s-CH-C4He or CHa = CH-CaH
An ethylene-tetrafluoroethylene copolymer having a content of 0.1 to 10 molti (units derived from ll), preferably from O.% to 5 molti, is preferably used. This ethylene-tetrafluoroethylene copolymer is known per se, for example,
It can be produced by the method described in Publication No. 50163,
In addition, Asahi Glass ■ “Aflon@C0PJ” is available as a commercial product.
It is also possible to use a product commercially available under the trade name .

Molding of the film from the above-mentioned fluororesin can be carried out in accordance with classified methods, for example, by extrusion molding, inflation molding, and the like. When forming a film, a coloring agent (for example, titanium oxide, zinc white, calcium carbonate, precipitated silica, carbon black, chrome yellow, phthalocyanine blue, phthalocyanine green, etc.) can be blended with the fluororesin as necessary. ′ If the thickness of the film is too thin, it will easily tear, and if it is too thick, it will not only be uneconomical, but also cause inconvenience in film production and subsequent handling (cutting, gluing, stretching, etc.). Since there is a possibility that the light transmittance also decreases, the
Conveniently, it is within the range μ.

In the fluorine film according to the third aspect of the present invention, it is important to perform a surface activation treatment on the fluorine film in advance in order to provide a coating layer containing an antifogging agent.

The surface activation treatment enables strong adhesion to the coating layer, and also prevents repelling of the solution during coating.

Examples of such surface activation treatment include methods such as corona discharge treatment, sputter etching treatment, sodium treatment, and sandblasting treatment.

Corona discharge treatment involves creating a discharge between a needle or knife electrode and a counter electrode, placing a sample between them, and treating the film with oxygen, such as aldehydes, acids, alcohol peroxides, ketones, and ethers, on the surface of the film. This is a process that generates functional groups.

Sodium treatment is a process in which the film is immersed in a liquid ammonia solution containing an alkali metal such as metallic sodium.
This process eliminates CFi bonds from the surface and generates CH, C-0 bonds.

In the sputter etching process, a sample is placed between electrodes undergoing low-pressure glow discharge, and a large number of fine protrusions are formed on the film by the impact of positive ions generated by the glow discharge.

Sandblasting involves blowing fine sand onto the film surface to form a large number of fine irregularities on the surface.

Among these surface activation treatments, corona discharge treatment is preferred in terms of adhesion to the coating layer, workability, safety, cost, and the like.

The coating layer containing the antifogging agent may be formed by coating the antifogging agent itself, or by coating a mixture of the antifogging agent and a binder solution.

It is important that the coating layer containing the antifogging agent in the present invention contains a surfactant effective as an antifogging agent, a hydrophilic polymer, a particulate inorganic substance, or a mixture of 2 m or more of these. .

Examples of such surfactants include sorbitan fatty acid ester, sorbitol fatty acid ester, diglycerin fatty acid ester, glycerin fatty acid ester, sorbitan fatty acid dibasic acid ester, sorbitol fatty acid dibasic acid ester, and diglycerin fatty acid dibasic acid ester. , glycerin fatty acid dibasic acid esters, and compounds obtained by adding alkylene oxides such as ethylene oxide and propylene oxide to these.

Examples of hydrophilic polymers include polyvinyl alcohol, polyvinylpyrrolidone, -80a,
-80sH, -COOH, -NHi, -CN.

Polymers having generally hydrophilic functional groups such as -(OCHsCHs) are included.

In addition, examples of particulate inorganic substances include silica, alumina, titanium oxide, and the like.

As a binder, (meth)acrylic acid ester resin,
Examples include vinyl acetate resin.

A solvent, additives, etc. may be added to the coating composition containing the above-mentioned antifogging agent for the purpose of improving workability, improving narrow surface smoothness, etc. Examples of solvents include water, various alcohols,
Ketones, esters.

Ether etc. can be used as appropriate.

As a method for applying the coating composition to the fluororesin film, commonly known methods such as brush coating, dip coating, gravure coating, and spray coating can be used.

In the present invention, surfactants, hydrophilic polymers, and particulate inorganic substances alone are sufficiently effective as antifogging agents in the coating layer, but in combination with particulate inorganic substances such as silica and alumina, polyvinyl alcohol, and polyvinylpyrrolidone. By doing so, further anti-fogging effects and longer-lasting effects can be obtained.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples and Reference Examples.

Example 1 3.46 Kg of trichloromonofluoromethane, 6.52 Kf of trichlorotrifluoroethane, and 2.38 N of t-butyl peroxyisobutyrate were charged into an autoclave with an internal volume of 101, followed by 1226 Ii of pthrafluoroethylene and 821 Kf of ethylene. and perfluorobutylethylene (CHa CH-Care) 261. While stirring this mixture thoroughly, the reaction temperature was increased to 65°C.
℃ to carry out copolymerization. During the copolymerization reaction, the molar ratio of tetrafluoroethylene/ethylene/perfluorobutylethylene was 53/46.3/
A mixed gas of 0.7% was introduced, and the polymerization pressure was increased to 15%. OKf
/cIl. After 5 hours, a white copolymer of 4601 was obtained. The copolymer consists of CaF4/CI H4/
The molar ratio of CHa m qHCa F* is 53/4
6.3/0.7, the flow start temperature g was 67°C, and the thermal decomposition start temperature was 360°C.

Ethylene-tetrafluoroethylene copolymer obtained above (hereinafter sometimes abbreviated as ``I!1TFFf'')
was extruded at a resin temperature of 320° C. to produce a film with a thickness of 60 μm.

One side of the obtained film was subjected to corona discharge treatment under the conditions of a discharge current of 10 people, a discharge voltage of 120 V, and a line speed of 15 rtt/mln. To the treated surface, a mixture of alumina sol (alumina solid content 15''%) and polyvinyl alcohol 4WtIs%ff5 was diluted 15 times with water and applied to give sy77FI!
And so.

Examples 2 to 4 Polyvinylpyrrolidone 5 was added to silica sol (silica solid content: 15 t) on the treated side of the single-sided treated film formed in Example 1.
The material to which wt% was added was diluted 50 times with water and applied to 5N/g as substrate 2 (Example 2).
Similarly, add 50% silica sol (silica solid content 15%) to water.
Covering material 3 (Example 3) was prepared by diluting sorbitan monolaurate 100 times with ethanol and applying it to give 51/r.
The material coated to give rl was designated as substrate 4 (Example 4). It was subjected to various tests and the results are summarized in I-1.

Comparative Examples 1 to 4 As a comparative example, the fluororesin film formed in the example was not subjected to narrow-sided activation treatment, and one side was coated with alumina sol (alumina solid content 15 wt1) and polyvinyl alcohol 4 wt.
ts was added, diluted 15 times with water, and sp.
/ , 1 was applied as building material 5 (comparative example 1).
), the fluororesin film formed in the example and without a coating layer was used as substrate 6 (comparative example 2), and the Six Light Three-Nine (Teijin 1 group polyester ultra-durable agricultural hard film) was used as substrate 7 (comparison). Example 3), Noviace (Mitsubishi Kasei Vinyl ■Crack, general agricultural vinyl film, thickness 0.1 mm)
) was used as the equipment 8 (Comparative Example 4), and various tests were carried out in the same manner as in the Examples, and the results are summarized in Table 1.

The various test methods and evaluation methods carried out in the Examples and Comparative Examples are as follows.

(1) Anti-fog properties at low temperatures Place the anti-fog layer on the inside, cover it on a beaker with a sluice at 20°C, place it in an atmosphere at 5°C, and check the anti-fog properties after 1 hour. Sympathize.

"Evaluation Criteria" 5- Completely anti-fogging with a water droplet adhesion area of less than 10% 4- Items with jF in the range of 10 or more and less than 30% 3- Items with #30 or more and less than 50% ffi Numono 2-7 Items in the range of 50 or more to less than 70% 1- Items with no anti-fog properties at all and below 77096 (2) Persistent anti-fog properties with the anti-fog layer on the inside, and then soaked in 40℃ hot water The solution was coated on a beaker containing 100% water, kept as it was for 6 months, and the anti-fog retention property was observed for 6 months.

"Evaluation Criteria" 5 - Completely maintains anti-fog properties with an anti-fog degraded area of less than 10% 4 - Items in the range of #'IO or more to less than 30- 3 - Anti-fog degraded areas of 30 or more - Less than 50% 2 - # 50 or more - less than 70% 1 - # 70% or less and no anti-fog properties at all (3) Weather resistance evaluation Facing south, flat surface The coating material is exposed on an outdoor platform installed at an angle of 45 degrees, and after a predetermined period of time, a portion of each film is removed and the film appearance and residual elongation at break are evaluated.

"Evaluation Criteria" 5- Those with a residual elongation rate of 80- or more without any change in appearance 4-
# # In the range of 60 or more to less than 5 Ots 3 - Appearance changes such as discoloration are observed and the remaining elongation rate is 40 or more
Items in the range of less than 60 2 - Appearance changes such as discoloration are observed on the entire surface and the remaining elongation rate is 20
Items in the range from above to less than 40 inches 1 - Appearance changes such as discoloration are observed on the entire surface and the remaining elongation rate is 20% or less (4) Dustproof evaluation From the exposure stand for the evaluation in (3) above. The light transmittance at a wavelength of 550 nm was measured for each removed coating material. The higher the transmittance, the better the dustproof property.

〔Effect of the invention〕

By using fluororesin, the present invention has properties superior to conventional agricultural coating materials in terms of weather resistance, dust resistance, and mechanical strength. It has excellent effects in that it provides a long-lasting overseas protection effect and does not reduce light transmittance.

Claims (1)

[Scope of Claims] 1. An anti-fog agricultural coating material, characterized in that a coating layer containing an anti-fogging agent is provided on the treated surface of a fluororesin film, at least one surface of which has been surface-activated. 2. The antifogging agricultural coating material according to claim 1, wherein the fluororesin film is an ethylene-tetrafluoroethylene copolymer. 3. The ethylene-tetrafluoroethylene copolymer is
The molar ratio of ethylene/tetrafluoroethylene is 40
/60 to 60/40, and the formula CH_2=
CH-C_nF_2_n_+_1 (where n is 2 to 1
Claim 2, which is an ethylene-tetrafluoroethylene copolymer having a content of perfluoroalkylvinyl monomer units represented by (an integer of 0) in the range of 0.1 to 10 mol%. anti-fog agricultural covering material. 4. The antifogging agricultural covering material according to claim 1, wherein the fluororesin film has a thickness within the range of 10 to 300μ. 5. Anti-fogging agriculture according to claim 1, characterized in that the coating layer containing the anti-fogging agent contains at least one selected from particulate silica, alumina, and titanium oxide. Coating materials for use.